1. Field of the Invention
The inventions relate to a capillary reservoir system for writing medium for writing instruments such as fiber-tip pens, liners and markers, consisting of several individual reservoirs which contain fibrous material. An economical variant according to another proposal contains only one fibrous material reservoir. The invention also relates to a capillary reservoir for colorant--as one of the above-mentioned individual reservoirs--for use in the above-mentioned writing instruments. Finally a process for the production of said colorant reservoir is proposed.
2. Prior Art
Writing instruments are known in a great variety of shapes which contain a liquid writing medium. In such cases the writing medium supply chamber may consist of a refillable supply container or a replaceable cartridge. In the case of fiber-tip pens, a capillary reservoir, e.g. a tampon or a package of fibrous material is provided in the housing of the writing instrument which contains a predetermined supply of ready-to-use writing medium. This supply is assigned to it during manufacture and determines the operating life of the writing instrument (cf. U.S. Pat. No. 3,481,677). When the above-mentioned cartridges are used, then environmental protection problems arise since the waste products--usually plastic cartridges--must be disposed of.
If a built-in writing medium reservoir is provided in the writing instrument which stores a predetermined quantity of writing medium, this quantity is limited a priori. After the previously stored quantity of writing medium has been released the writing instrument is empty and--like the cartridges--must be disposed of. To this one may add the problem that the predetermined quantity of writing medium decreases as a function of age even if the writing instrument is not used, that is to say, when it is on the shelves of the retailers and wholesalers for shipping and sales.
A refillable capillary writing medium reservoir system has become accessible to the technical world from WO 92/18339. It discloses a front and rear reservoir but does not disclose a central individual reservoir which stores the color component contains fibrous material. A "marking or coloring pen" (marker) is described in U.S. Pat. No. 3,993,409 (Hart). In two examples there markers are described which display two individual reservoirs. They are telescoped into one another. One of the reservoirs is the writing tip (or the "writing wick"), the other is the liquid reservoir. The latter is clearly larger than the former. In Hart the individual reservoirs are arranged in one another not on one another, the size dimensions are also contrary to the object of the invention. To be sure the writing wick in Hart also stores the writing fluid and color pigments simultaneously.
U.S. Pat. No. 3,993,409 (Hart) discloses an elongated reservoir having fibrous material filled with a colorant for the production of liquid writing medium which is stored between the fibers, but not a shell permeable for liquid and gasses. Placing a shell around the wick of Hart would be equivalent to making the Hart marker function less which is based on the telescoping--in contact of the outside of the wick and the inner hole (boring) of the plug for its function.